The long term objective of this Clinical Research Center is to develop improved assessment and rehabilitation procedures for individuals with speech disorders of neurologic origin. Research is to be conducted in three major areas, each of which contributes information on the normal or abnormal neuromotor control of speech: (1) Research on normal speech motor control includes studies of maturation in normal children and of regulatory mechanisms in the normal adult. (2) Studies of abnormal mechanisms are designed to reveal the nature of the speech motor problems that accompany several neurologic disorders, (including spasticity, athetosis, ataxia, Parkinsonism, and peripheral lesions) that affect different motor centers of the nervous system. (3) Experiments in speech rehabilitation will focus on the (a) efficacy of biofeedback with selected individuals, and (b) prosthetic management of the velopharynx in various neurologic conditions. The methods used to study neuromotor control in all three of these areas include recordings of the acoustic speech signal, structural movements, aerodynamic variables, and muscle action potentials. The data collected from normally developing children, normal adults, and adult neurologic subjects will be used to form hypotheses and refine methods for the subsequent study of neurological speech disorders in children.